This was not a RTFM question. Actually I think you're the first to ask it (At least since I joined this forum)

People sometimes ask what is taking up so much e space, but otherwise no.

Might be good to include it here:

Partly downloaded files that you cancel in the dowload window are not deleted from the incomplete folder, in case you want to continue them later. They should be deleted from them manually if not wanted. Same goes for previewed files. They are copied in the incomplete folder.

In case you do this outside of Limewire, DO NOT delete the Downloads.dat and Downloads.bak files unless you want to start clean, as they keep all the info on pending and completed downloads.